Side by side

Bremont Supermarine 300MvsSeiko Prospex Sea

The numbers, the dial colors, the calibers — laid out so you can stop flipping between tabs.

Supermarine 300M
BremontSupermarine 300M
MSRP $3,550
Prospex Sea
SeikoProspex Sea
MSRP $1,100

At a glance

11 of 29 specs differ
Diameter
Supermarine 300M40mm
Prospex Sea41.3mm
Power Reserve
Supermarine 300M40h
Prospex Sea72h
Water Resistance
Supermarine 300M300m
Prospex Sea300m
MSRP
Supermarine 300M$3,550
Prospex Sea$1,100

Full specifications

Case

4 specs
Diameter
40mm
41.3mm
Thickness
12mm
12.5mm
Lug-to-Lug
48.2mm
Material
904L Stainless Steel
Stainless Steel

Crystal & Dial

3 specs
AR Coating
Inner
Anti-reflective coating on inner surface
Dial Color
Green
Black
Lume
None
LumiBrite on hands, index(es) and bezel

Movement

3 specs
Caliber
BE-92AE
6R55
Power Reserve
40h
72h
Jewels
25
24

Pricing

1 specs
MSRP
$3,550
$1,100

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What people say

Owners + reviewers, side by side

Synthesized for each watch independently from owner discussions, enthusiast forums, written reviews, and video reviewers.

Bremont Supermarine 300M

The Bremont Supermarine 300M is praised for its comfortable 40mm and 42mm case sizes, with owners noting the 42mm wears well on smaller wrists due to its lug design. One owner highlights the 13mm thinness of the 40mm case, considered compact for a 300m diver. The watch is priced at $1375. On balance, owners and reviewers appreciate the Bremont Supermarine 300M for its wearability and compact dimensions, especially for a dive watch.

Seiko Prospex Sea

Seiko Prospex Sea models are widely praised for their excellent build quality, value for money, and comfortable wearability, with many appreciating the vintage-inspired designs and robust construction. Owners note the silicone straps are surprisingly comfortable and well-finished, and the Lumibrite lume is excellent. However, some find the 44.3mm size and thickness too large for smaller wrists, though others report the sizing as perfect. The 6R15 movement in some variants offers accuracy around +4 seconds per day with a 50-hour power reserve, while newer movements offer more. Some models are criticized for a bracelet width not matching the case size or a rudimentary clasp for their price point. Overall, owners and reviewers rate the Seiko Prospex Sea highly for its impressive case work and finishing at its price point.

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